using System; 
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Linq.Expressions; 

namespace System.Data.Linq { 
    /// <summary> 
    /// Encodes the rules for subqueries.
    /// </summary> 
    static class SubqueryRules {
        /// <summary>
        /// This list of top-level methods that are supported in subqueries.
        /// </summary> 
        /// <param name="mi"></param>
        /// <returns></returns> 
        static internal bool IsSupportedTopLevelMethod(MethodInfo mi) { 
            if (!IsSequenceOperatorCall(mi))
                return false; 
            switch (mi.Name) {
                case "Where":
                case "OrderBy":
                case "OrderByDescending": 
                case "ThenBy":
                case "ThenByDescending": 
                case "Take": 
                    return true;
            } 
            return false;
        }
        private static bool IsSequenceOperatorCall(MethodInfo mi) {
            Type declType = mi.DeclaringType; 
            if (declType == typeof(System.Linq.Enumerable) ||
                declType == typeof(System.Linq.Queryable)) { 
                return true; 
            }
            return false; 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.